存储访问框架 - 无法从 uri 获取文档树（从 Drive 应用程序返回）

Question

我的 Android 应用想要在 Google Drive 中创建一个文件夹并从设备上的 Drive 应用获取 uri。

它发送一个intent，你可以看下面的代码：

private void createFolder(String folderName) {
    Intent intent = new Intent(Intent.ACTION_CREATE_DOCUMENT);
    intent.addCategory(Intent.CATEGORY_OPENABLE);
    // Create a file with the requested MIME type.
    intent.setType("vnd.android.document/directory");
    intent.putExtra(Intent.EXTRA_TITLE, folderName);
    startActivityForResult(intent, WRITE_REQUEST_CODE);
}

然后获取返回的数据，可以看下面的代码：

@Override
protected void  onActivityResult(int requestCode, int resultCode, Intent resultData)
{

    if (requestCode == WRITE_REQUEST_CODE && resultCode == Activity.RESULT_OK) {

        Uri uri = null;
       if (resultData != null) {
            uri = resultData.getData();
            Log.i("result", "Uri: " + uri.toString());
            DocumentFile pickedDir = DocumentFile.fromTreeUri(this, uri); //this line gives the error
                       }
    }

}

我使用了一种在 Internet 上找到的 mimetype，它似乎是一种标准类型。使用“application/vnd.google-apps.folder”时也会出现同样的错误。 目标是拥有一个文档树，但在 logcat 中我收到以下错误：

java.lang.RuntimeException: Failure delivering result ResultInfo{who=null, request=43, result=-1, data=Intent { dat=content://com.google.android.apps.docs.storage/document/acc=1;doc=encoded=LongStringWithRandomCharactersHere/j flg=0x43 }} to activity {com.example.myapplication/com.example.myapplication.MainActivity}: java.lang.IllegalArgumentException: Invalid URI: content://com.google.android.apps.docs.storage/document/acc%3D1%3Bdoc%3Dencoded%3DSameLongStringWithRandomCharactersHere%2Fj

及以下

Caused by: java.lang.IllegalArgumentException: Invalid URI: content://com.google.android.apps.docs.storage/document/acc%3D1%3Bdoc%3Dencoded%3DAnotherLongStringWithDifferentRandomDataHere

这是完整的堆栈跟踪：

2019-05-31 15:06:50.167 31184-31184/com.example.myapplication E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.example.myapplication, PID: 31184
java.lang.RuntimeException: Failure delivering result ResultInfo{who=null, request=43, result=-1, data=Intent { dat=content://com.google.android.apps.docs.storage/document/acc=1;doc=encoded=randomcharacters flg=0x43 }} to activity {com.example.myapplication/com.example.myapplication.MainActivity}: java.lang.IllegalArgumentException: Invalid URI: content://com.google.android.apps.docs.storage/document/acc%3D1%3Bdoc%3Dencoded%3Drandomcharacters
    at android.app.ActivityThread.deliverResults(ActivityThread.java:4365)
    at android.app.ActivityThread.handleSendResult(ActivityThread.java:4409)
    at android.app.ActivityThread.-wrap19(Unknown Source:0)
    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1670)
    at android.os.Handler.dispatchMessage(Handler.java:106)
    at android.os.Looper.loop(Looper.java:164)
    at android.app.ActivityThread.main(ActivityThread.java:6687)
    at java.lang.reflect.Method.invoke(Native Method)
    at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:438)
    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:810)
 Caused by: java.lang.IllegalArgumentException: Invalid URI: content://com.google.android.apps.docs.storage/document/acc%3D1%3Bdoc%3Dencoded%3Drandomcharacters
    at android.provider.DocumentsContract.getTreeDocumentId(DocumentsContract.java:1023)
    at android.support.v4.provider.DocumentFile.fromTreeUri(DocumentFile.java:138)
    at com.example.myapplication.MainActivity.onActivityResult(MainActivity.java:254)
    at android.app.Activity.dispatchActivityResult(Activity.java:7295)
    at android.app.ActivityThread.deliverResults(ActivityThread.java:4361)
    at android.app.ActivityThread.handleSendResult(ActivityThread.java:4409) 
    at android.app.ActivityThread.-wrap19(Unknown Source:0) 
    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1670) 
    at android.os.Handler.dispatchMessage(Handler.java:106) 
    at android.os.Looper.loop(Looper.java:164) 
    at android.app.ActivityThread.main(ActivityThread.java:6687) 
    at java.lang.reflect.Method.invoke(Native Method) 
    at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:438) 
    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:810) 

uri 没有错，因为我可以进一步提取在云端硬盘上成功创建的文件夹名称（并且大小=0）。 相反有什么问题？看来我的应用程序无法将其作为文档树处理。

Answer 1

这适用于 Google Drive 云空间，但它可能是一个 hack。不能保证始终有效。

此示例在用户创建的云文件夹中创建云文件（SAF 选择器由应用打开）。

创建云文件夹（用户必须先从选择器 UI 中选择云根目录）

 Intent intent = new Intent(Intent.ACTION_CREATE_DOCUMENT);
 intent.setType("vnd.android.document/directory");
 intent.addFlags(Intent.FLAG_GRANT_PERSISTABLE_URI_PERMISSION);
 intent.addFlags(Intent.FLAG_GRANT_READ_URI_PERMISSION);
 intent.addFlags(Intent.FLAG_GRANT_WRITE_URI_PERMISSION);
 startActivityForResult(intent, CREATE_DIRECTORY_REQUEST_CODE);

onActivityResult

@Override
protected void onActivityResult(int requestCode,int resultCode, Intent data) 
{
    super.onActivityResult(requestCode, resultCode, data);
    if (requestCode == CREATE_DIRECTORY_REQUEST_CODE) 
    {
      if (resultCode == Activity.RESULT_OK) {
      int takeFlags = data.getFlags()
                   &
      (Intent.FLAG_GRANT_READ_URI_PERMISSION | Intent.FLAG_GRANT_WRITE_URI_PERMISSION);
      ContentResolver resolver = this.getContentResolver();
      resolver.takePersistableUriPermission(data.getData(),takeFlags);
      archiveUri(data.getData().toString()); //important to save the toString() result, not getPath()
      archiveAuthority(data.getData().getAuthority());
      } 
      else 
      {
            // The user cancelled the request.
      }
    }
}

下次使用 Uri

ContentResolver contentResolver;
contentResolver = this.getContentResolver();
uriPath=retrieveArchivedUri();
Uri tempUri;
Uri uri; 
String authority;
tempUri=Uri.parse(uriPath);
authority=retrieveArchivedAuthority();
uri= DocumentsContract.buildDocumentUri(authority,
            DocumentsContract.getDocumentId(tempUri)); //folder Uri

try 
{
 DocumentsContract.createDocument(contentResolver,uri,"plain/text","fileName");
} 
catch (FileNotFoundException e) 
{
        e.printStackTrace();
}